Option Number

Option Name

Source

Description

1

Subnet Mask

RFC 2132

The subnet mask to apply to the address that is assigned to the client.

3

Gateway

RFC 2132

Tells the client which router is the default router.

6

Domain Name Server

RFC 2132

Carries the IP address(es) of the DNS servers that the client uses for name resolution.

15

Domain Name

RFC 2132

Carries the domain name portion of a client’s fully qualified domain name (FQDN).

17

Root Path

RFC 2132

This option specifies the path-name that contains the client's root disk.

28

Broadcast

43

Vendor Specific Information

RFC 2132

Carries some configuration data that is not defined in the standard DHCP RFCs.  Individual vendors can define different pieces of data that may be found in this option. Sub option 1=PXE MFTPD IP

51

Lease Time Option

RFC 2132

This defines the maximum amount of time that the client may use the IP address.

54

DHCP Server

RFC 2132

This option is used in DHCPOFFER and DHCPREQUEST messages, and may optionally be included in the DHCPACK and DHCPNAK messages.  
DHCP servers include this option in the DHCPOFFER in order to allow the client to distinguish between lease offers.  
DHCP clients use the contents of the 'server identifier' field as the destination address for any DHCP messages unicast to the DHCP server.  
DHCP clients also  indicate which of several lease offers is being accepted by including    this option in a DHCPREQUEST message.
 The identifier is the IP address of the selected server.

60

Vendor Class Identifier

RFC 2132

Carries some identifier from the client that may identify the client’s device class. The DHCP specification does not define what values go into this field, but other specifications do.

66

TFTP Server Name

RFC 2132

Carries the FQDN or IP address that the device should use to download the file specified in option 67.  

67

Filename

RFC 2132

Carries the filename that is to be downloaded from the server specified in option 66.

252

Private

Individual vendors can define different pieces of data that may be found in this option,